(1) Field of the Invention
The present invention relates to electrodes and more specifically to a bipolar electrode and its fabrication for use in a separated flow semi-fuel cell.
(2) Description of the Prior Art
Prior art energy sources such as the Zn/AgO electrochemical couple are not suitable for certain applications because of their low energy density. There is a requirement for energy sources with high energy density that are relatively inexpensive, environmentally friendly, safe to operate and reusable, have a long shelf life, are capable of quiet operation and are not prone to spontaneous chemical or electrochemical discharge. In particular, such an energy source would be ideal for long endurance applications as would be required for the propulsion of underwater vehicles such as unmanned underwater vehicles.
Specific types of semi-fuel cells are being developed in an effort to meet the high energy density requirements of unmanned underwater vehicles. To achieve high energy and long endurance, a multicell stack is required. This necessitates the fabrication of bipolar electrodes having a metal anode on one side of the electrode and a catalyst cathode on the other side. In order for a bipolar electrode to function properly, the metal anode side of the bipolar electrode must be electrically connected to the catalyst cathode side. This presents a problem because at the same time the catalyst cathode must be physically isolated from the anolyte, and the metal anode must be physically isolated from the catholyte. There is presently no bipolar electrode designed such that the anode side is electrically connected to the catalyst cathode side and physically separated from the catholyte in a semi-fuel cell. What is needed is the bipolar electrode of the present invention wherein the metal anode is connected to the catalyst cathode through a laminate of conductive adhesive bonded to two sides of a sheet of conductive foil that also physically separates the metal anode from the corrosive catholyte.